I was doing some light reading earlier and ran across the chapter where plate joining was described, but I was unsure as to exactly what he meant. There is a picture but ... it's ... well idnyou have the book you know.

So there is a bumper on both sides then somehow uses wedges to tighten the joint in the middle. Maybe it's just me, but I didn't really grasp what was going on. Any insight?Thanks.B

Hesh, is the tutorial you referenced in the link above available somewhere? The link is dead. I saw the tutorial here by Chris P, is it the same method? I assume so, there are only so many ways you can stretch tape.

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_________________"Is this the one where I trot downfield and act like I'm lost ?" - Billy Bob

I still use a variation of the Cumpiano/Natelson method, because it goes fast after the dry run is set up, and I use hot hide glue, so fast is good. I have a workbench that is 30" wide, and a silicone pad between the bench and the top being glued, so I skip the separate piece of plywood and the wax paper. Otherwise, what I do looks a lot like John's first photo above.

We use a combination of the tape (or tent) method and Mr. Cumpiano's approach. Both have advantages and disadvantages - the combination eliminates the issue with poor glue line pressure and side-to-side misalignment issues which can be seen in the tape method and the time-consuming alignment step in the Cumpiano method that makes hot hide glue a bit more of a challenge.

A 24" x 24" x 3/4" plywood fixture is used - we also use the fixture (with 1/4" centering pin) for working rosettes, and the fixture is stored with our radius dishes and height adjustment shims for the go-bar deck. A fixed 4" wide x 1/2" - 3/4" plywood fence is screwed to the face of the fixture along one edge, and four scrap plywood blocks along the opposite edge. Four short wedges provide the glue line pressure, and an elevated 1-1/2" square poplar or maple bar provides the bearing surface to wedge the show face of the plate against the fixture for alignment of the two sides. The glue line pressure is the same whether a fence or another set of stops and wedges is used. For irregularly shaped plates (such as frequently seen with Brazilian rosewood sets), a second set of stop blocks is used, with all of the stop blocks placed and screwed to the fixture as needed to provide uniform glue line pressure.

Attachment:

Joining-SJ-Redwood-Top.jpg

In terms of the procedure:

- Joint the plate and trim to width and length (we use the top off-cuts for the centerline graft on the back plate)

- If necessary, use a spacer shim between the fence and plate so that it can be wedged face-up in the fixture. A piece of repurposed copier paper is split lengthwise and is placed under the joint to address any glue squeeze-out which manages to make it's way between fixture and plate.

- Lightly wedge the plate into the fixture face-up; make sure the edges of the joint are well aligned

- Use six or seven 12"-14" long pieces of 1" strapping tape (or other strong, stretchy tape) to tape across the plate; these pieces of tape will act as a hinge to allow the joint to be opened for gluing while still maintaining alignment

- Use one piece of low-tack blue tape to cover the center area between the two halves of the plate - this prevents glue from leaking through the joint prior to it being closed

- Remove the wedges, flip the taped plate over in the fixture such that the show face (the taped side) is now against the fixture; place a 2-1/2" x 3/4" x 3/4" block of scrap ply under each end of the center seam. This opens the joint for gluing (the plate now looks a bit like the sort of pup tent which the Girl Scouts used to use for overnight camping trips).

- Run a bead of hot hide glue (or lesser adhesive) along the open joint and remove the blocks - the plate will close

- Weight one side of the plate with a 5 pound weight (a jack plane is ideal), and lightly wedge into place

- Clean off the squeeze-out with a putty knife and damp paper towel, use another piece of copier paper to keep any squeeze-out from adhering to the wedges, then clamp the pressure bar in place using the scrap blocks to elevate; use 15-20 long wedges to clamp the joint to the fixture, then tap the side wedges tight

- Remove the jack plane (it is used solely to avoid the plate reopening when wedged)

- Removal of the plate is done by first removing the side wedges, then unclamping the pressure bar. The protective paper strip away easily, and a little heat will aid in stripping away the tape without pulling any wood fibers loose.

It is worth notching the inside corners of one of the plate halves, as the joint will likely be invisible once the plate is thinned and smoothed. Also - 5 degree wedges seem to work quite well for the task, and we have two wall-hung storage bins set up with 4 short and 20 long wedges, plus the small blocks of scrap used in the process. A 12 roll pack of 3M 1" filament (aka strapping) tape is just over $5 per roll, and is also our favorite tape for binding (will not cut on a sharp edge, and is much stronger than paper tapes while still being just stretchy enough to provide good pressure while the glue is drying).

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_________________Tolerance is the virtue of the man without convictions. - G.K. Chesterton

Thanks for the pictures and suggestions! Very helpful. As for the tape.... how in the crap do you keep it from pulling out grain when you remove it? Yea that's a noob question ha

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Put a drop of alcohol at the edge of the tape so it will wick along, attacking the adhesive as you peel it. Works even better if the surface has been shellacked before putting tape on it, so the fibers are somewhat glued together, and the wood can't absorb the alcohol so quickly.

But that's mainly for binding. For plate joining, I use blue masking tape, which is gentle enough to peel off without any special care.

I use the tape method. I use the cheapest masking tape I can find. One piece stretched the length of the joint, 4 or 5 pieces stretched across the same side, "tent" the plates, apply HHG, flip and stretch 4-5 pieces of tape on the other side, clamp a spring clamp on the top and bottom edge and hang from a hanger so air can circulate on both sides of the plates. I will do several sets of plates at the same time. I leave them a little bit thick and run them through a thickness sander after they are completely dry.

All plates have some run-out, so pulling the tape parallel to the grain and in the direction of the rising grain minimizes any torn wood fibers. The direction of rising grain changes between sides of the plate, so (as an example) if the treble side of the plate has grain which rises towards the nut, each piece of tape is peeled from outer edge of plate towards centerline and along the grain towards the neck on the treble side, and towards the tail block on the bass side of the plate. I have some shots of this somewhere, but they are mixed in with a thousand others! Try this on a scrap top - the only challenge is determining which direction the grain rises, and that is quickly answered by peeling in the wrong direction.

Attachment:

PhotoReqChapter8TapeRemoval01.jpg

The alternative is to gently heat the tape and remove; too much heat leaves the adhesive on the plate and not enough results in wood being lost. A combination of both techniques (heat and directional peeling of tape) will handle even the most troublesome woods.

Be careful using solvents on/adjacent to woods that bleed, such as rosewoods. This is usually not an issue on plate glue-ups, but very much a concern when removing binding tape from woods such as cocobolo or African blackwood. Some woods bleed only into non-polar solvents such as common alcohols or petroleum-based solvents such as naphtha, and some bleed only with polar solvents like water; coco bindings can make a mess of adjacent purfling or light-colored top or body woods because they bleed with either type of solvent. Cedar has some non-polar solvent-soluble extractives which may 'water-mark' the surface if the solvent is not uniformly applied, and even a trace of rosewood dust on a spruce top may cause staining where that dust comes in contact with solvent.

Edit: I have the photo request from the draft - not my artwork, so no comments, gentlemen! Yes - those are supposed to be hands, and no - no hand models were harmed in the making of that sketch.

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_________________Tolerance is the virtue of the man without convictions. - G.K. Chesterton

Hesh, is the tutorial you referenced in the link above available somewhere? The link is dead. I saw the tutorial here by Chris P, is it the same method? I assume so, there are only so many ways you can stretch tape.

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Hey Brad. I can't find that toot on the OLF so it must have died some years back.

I believe that I have it in the cloud someplace if anyone wants me to throw it back up here in the toot section. It's a great method, super simple and best of all many of the guitars that I used it with are over a decade old now and any issues would have showed up by now.

All you need is tape, no special tape either, some waxed paper, glue and any old thing for weights.

IMHO The Cumpciano method is so simple, why would you not use it. Woods G's set up is slick. I dumb it down a bit.

Get the stops set up in the right place. I use 2 wedges on each driven opposing each other. Glue your board and make the join. Put the wedges in place with light pressure. If there is plenty of thickness I flush up by hand or is they are a little thin, I lightly tap with a hammer the get the plates flush. Put a fairly heavy tool box on top of the plates and drive the wedges home.

So simple!

Last edited by DannyV on Sat Oct 07, 2017 12:54 pm, edited 1 time in total.

I guess some folks like the idea of using a stand-alone jig like the rope & wedges method because you can remove it from the workbench and set it aside, making room for another operation. My bench is 5 feet long, 2.5 feet wide, so I can afford to let the top or back dry overnight and have room on the other end of the bench to do something else. I agree with Danny that I have not had any need to get fancier than the Cumpiano/Natelson method, so I just stick with it (with minor variations, described above).

Be careful using solvents on/adjacent to woods that bleed, such as rosewoods. This is usually not an issue on plate glue-ups, but very much a concern when removing binding tape from woods such as cocobolo or African blackwood. Some woods bleed only into non-polar solvents such as common alcohols or petroleum-based solvents such as naphtha, and some bleed only with polar solvents like water; coco bindings can make a mess of adjacent purfling or light-colored top or body woods because they bleed with either type of solvent. Cedar has some non-polar solvent-soluble extractives which may 'water-mark' the surface if the solvent is not uniformly applied, and even a trace of rosewood dust on a spruce top may cause staining where that dust comes in contact with solvent.

Right, the top/back/sides should be shellacked before routing the binding channels for this method. Then it's only the binding itself that might bleed, and only the purfling is vulnerable to staining, which will be removed when scraping level.

I started out using the wedges after seeing them in the D R Young book. Weighted with old antique laundry irons. Added tape later so I could tent the plates for ease of glue application. Finally switched to Woody's setup after seeing a picture- I think from Woody"'s boss- here on the OLF. I use packing tape on the wedges so they won't stick.

All with hide glue.

Belt and suspenders. As mentioned, we may be overthinking this.

I use heat and alcohol for tape removal watching the runout. I'll put a little tape outside the top border and be sure what direction the fibers lift and put penciled arrow markers for later reference.

_________________It's not what you don't know that hurts you, it's what you do know that's wrong.

I really like the LMI jig because it keeps the plates flat along the joint. Woodie's method will accomplish the same thing. I taped a few guitars and liked the simplicity of it, but there were times when the plates wouldn't be perfectly flat along the joint, which made gluing thinner plates impossible for me.

This is the method I picked up from the person who taught me how to build guitars. It sets up and takes down fast, the clamping pressure is easy to control, and the clamps store nicely on the bottom shelf of the bench. They also have general uses besides joining plates. The disadvantage is cost. I got these ones at a very good sale though and I like using them.

Attachment:

Plate joining.jpg

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_________________Once in a while you get shown the light in the strangest of places if you look at it right - Robert Hunter

"I taped a few guitars and liked the simplicity of it, but there were times when the plates wouldn't be perfectly flat along the joint, which made gluing thinner plates impossible for me. "

Using slightly thicker plates with the tape method solves two problems - fibers torn out by tape removal and any slight misalignment of the plates is removed when the plates are (semi) final thicknessed after the glue has fully cured. I like to check the stiffness as I sand to thickness.

Last I saw, Robbie O'Brien had switched to the LMI jigs, but when I was learning, we pre-cut the scrap from the top, making the whole plate into a wedge and we'd put that on a board between 2 angled fences and drive the wedge shaped top into the fences. It's better to weight it down before banging it into place to keep it from bowing on you.

FWIW I use a very strong wide brown tape from u haul 2in wide.The secret is to use a ramped shooting board and a vy tight joint with 0 gap. I slide the glue along the joint tape and weigh it down with worn air nailers an weight. I ve used 5 different methods, all involve way more time.

I put together a test yesterday using the tape method. I used the green tape that I use for binding. It's very stretchy. I used hide glue and the joint is straight from the power jointer. I still have some work to do, it's not totally invisible. The pencil is pointing at the glue line.

For instruments I use the SM leveling beam with some sandpaper to complete the joint and I use a wedging jig. Those joints are invisible. Up to now I've used titebond but I'll use hide on the next build.

Brad

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_________________"Is this the one where I trot downfield and act like I'm lost ?" - Billy Bob

I'm uneasy about the idea of using hot hide glue with a ropes and wedges jig (i.e., the LMI jig or any homemade version). I am just imagining how much time it would take me to figure eight the ropes and slide in the wedges. But that's just me. Like I said above, the Cumpiano/Natelson method goes really fast after you set up the dry run; probably less than a full minute. I'm happy with my tailored version of it until something better comes along, and nothing has so far.

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